Wrapping tissue



Patented June 12, 1923.

UNITED STATES CARL P. OLSON, OF IRVINGTON, NEW JERSEY.

WRAPPING TISSUE.

No Drawing.

To all whom it may 0012mm: I

Be it known that I, CARL I. OLSON, a citizen of the United States, residing in the town of Irvington, county of Essex, and

State of New Jersey, have invented certain new and useful Improvements in Trapping Tissues, of which the following is. a specification.

My invention relates to wrapping tissues, and particularly to film-like wrappers of cellulose acetate tissue.

It has for its objects the provision of a thin, flexible, strong tissue which shall be non-porous, non-hygroscopic, non-inflammable, transparent and cheap, and adapted for all uses as a wrapping sheet for which tissues of paper or gelatine are now employed, but that shall be stronger than such tissues of equal thickness; that shall be of transparency equal to that of gelatine tissues of equal thickness, but, unlike such gelatine tissues, shall be non-brittle and highly flexible; that shall not be absorptive of moisture and liable to consequent deterioration,-

as is a gelatine tissue; that shall be impervious to dust and dirt; that shall afford a measure of protection against fire from flame, and that shall be capable of affording sanitary protection by its amorphous and non-porous texture to a contained article.

To these ends my invention consists in a wrapper of flame-retarding tissue made from an organic ester or esters of cellulose, such as esters of cellulose with the paraffin series of acids, such as acetic acid; or from cellulose or cellulosic compoiinds or derivatives with alcohol radicals, such as the ethyl or I other alkyl celluloses, benzy-lcellulose or other arylcellulose esters, for the purposes specified, as a new article of manufacture.-

While nitrocellulose and nitrocellulose compounds, and those bodies going under the enera-l name of viscose have been proposed or similar purposes, I disclaim their use in this connection as also the relatively inflammable esters of cellulose and mixtures or combinations in which they are an essential constituent or compound; together with any cellulose, cellulose derivative or cellulosic compounds or ester prepared therefrom which contain any acid radical adapted to render such compound inflammable.

In the preferred form of my invention I employ, as raw materials, cellulose, as cotton or tissue paper; glacial acetic acid, glacial; acetic anhydride, and a catalyst such as Application filed April 17, 1922. Serial No. 554,181.

a very small amount of sulfuric acid or zinc chloride. Th method of manufacture and quant tles of each may be as follows: Take The foregoing components, excepting the cellulose, are placed in a mixer, and agitated. During agitation the cellulose, properly dried, is fed in small quantities to the mix. After the cellulose has all become incorporated, which requires from 2 to 3 hours, the temperature being meanwhile maintained below 20 1., the cellulosic compound, will be found, upon test in chloroform free from ethyl alcohol, to be substantially insoluble. The process is then continued until the product, after precipitation and washing until neutral, is found to dissolve in warm, pure chloroform but not to dissolve in pure. acetone.

The product is then partially hydrated by the addition of about 3% of water, added in small amounts at a time. The hydrated product, a heavy, viscous, clear liquid, is then maintained at a temperature of 25 to 30 C. for several days, and until a sample is found to have lost its solubility in warm chloroform and to have acquired a complete solubility in cold or warm pure acetone. \Vhen this stage of ripening is reached, the batch is precipitated by added water, the batch being stirred during such addition of water thereto, and such washing is continued to neutrality in a manner similar to the treat ment of pyroxylin in heaters, except that the cellulose acetate is already in a state of fine subdivision from precipitation. This precipitated and washed cellulose acetate is next hydro-extracted and flowed, or otherwise spread, as by the methods and apparatus of my U. S. Letters Patent No. 1,387,068, granted me August 9, 1920, upon a film-forming medium, and dried at a moderate temperature in the form of a thin tissue of desired dimensions. While I am aware that it has been proposed to form a box and lid therefor of acetyl-cellulose and to line tubes or containers to make them fluid-tight with a film of cellulose acetate, or

to coat a paper receptacle with a cellulose ester solution to make same resistant to moist alkalis, I *believe it is broadly novel to produce a flat self-supporting sheet of acetyl cellulose, having the superficial dimensions in which paper is made, for example, double elephant writing or double royal printing, and of the thinness and fineness of the finest grade of tissue paper, which sheet is adapted by its size and quality to the utilities for oh the finer grades of wrapping paper ar customarily used. V

The tissue roduced is free from odour,

non-porous, p iant, transparent, and slowburning, and otherwise embodies the desired ualities and characteristics heretofore set orth as the desired objects-to be attained and realizes all the beneficial features of particular utility and advantage specified. In

sizes in which tlssue paper is customarily manufactured.

Having thus described my invention and the method practiced and means employed by me in producing the same in the form believed by me to be its embodiment, I

claim: v w

As a new article of manufacture, a wrapping sheet of tissue paper character composed of acetyl cellulose, ;-j

CARL 1P. OLSON. 

